"When Walmart abandoned one of its retail stores in McAllen, Texas, the city was left with the challenge of deciding what to do with the vacant building. Understanding that the greenest building is one that already exists, city officials decided to reuse the structure instead of tearing it down. The former big box store is now home to the McAllen Main Library. The primary challenge of reusing the building was to create a highly functional, flexible library of 125,000 square feet on a single level. This area is equivalent to nearly 2 1/2 football fields, making the new library the largest single-story library in the U.S.To meet this challenge, the designers had the old store interior and new mechanical systems painted white to form a neutral shell for new patron and service areas, which are designated with color. Primary program areas—including community meeting rooms, the children's library, adult services, and the staff area—are located in quadrants of the building. This clear organization allows easy wayfinding and patron access from a central service spine, delineated by a patterned wood ceiling that runs the length of the building. A secondary spine in orange runs perpendicular to the first to further distinguish the public community meeting rooms from the private staff area and the children's from the adult services areas. McAllen serves as the crossroads for thousands of species of insects and birds as they migrate seasonally between North and South America. To celebrate this unique local phenomenon, the design concept focuses on movement and migration. Forms, materials, patterns, and colors undulate through the space from floor to wall to ceiling to create elements that organize the space, provide landmarks for visitors, and modulate the scale of spaces within.The result is a new life for a building that would have otherwise ended up in a landfill."